This invention relates to protective membrane structures and especially to transparent film structures to provide temporary storm window protection.
There are very many temporary or presumably inexpensive structures to provide protection or sealing covers for windows or other openings. For example, there is the very early De Coursey U.S. Pat. No. 55,473 directed to a window mosquito net and the more recent Hoodis U.S. Pat. No. 2,237,778 directed to a drying cover to be affixed over a bathtub. While these two structures happen to be perforate structures to admit air or exclude mosquitos or to provide a drying surface, they are the closest tensioning arrangements which applicant has found in the prior art. Unfortunately it is almost impossible to achieve a really plane surface providing distortion-free viewing with such tensioning arrangements.
Accordingly it is an object of the present invention to provide a protective, flexible membrane structure having a tensioned plane surface which minimizes distortion produced by wrinkles or other surface irregularities.
Another object is to provide a temporary protective window which may be easily installed and removed.
A further object is to provide a protective, film-type storm window with effective sealing around the perimeter.